How to Fix 3D Printer Not Reading SD Card?

Many users may confront with Creality Ender 3 not reading SD card while printing. This can also happen on any other 3D printers. And the reasons can be quite different, and sometimes, trivial matters tend to be ignored especially by beginners.  This makes 3D printer not reading SD card a so frustrating problem. To help the users out, we've collected possible causes as many as we can, and meanwhile, correspondent solutions to fix these issues are included in this article that you should never miss.

Causes and solutions for Ender 3 not reading SD card

1. Inappropriate inserted SD card

It's quite common that when we get a good model to print and rush to the printer, but carelessly insert the SD card with inappropriate connection with the card slot. Either too loose SD card pin contact or opposite inserted SD card happens here.

Thus the first thing to do when Ender 3 doesn't read a SD card is to check if SD card is correctly inserted; if not, reinsert the SD card into the slot with correct pin orientation (usually pin side downwards, for example on the Creality Ender 3, only a few printers can be pin side upwards).

2. Dusty SD card or SD card slot

Either a dusty SD card or card slot can result in printer not reading SD card. Blow the card slot gently with a hair dryer and lightly wipe the SD card pins with a soft cloth (a glasses cloth is recommended).  Clean SD card and card slot is also important for the printer  to get access to the files inside the SD card.

3. Inappropriate file names

Too long (larger than 8 characters or even more) or space included G-code file names in the SD card are not that appropriate for some 3D printers to read. Shorten file names to be within 8 characters (typical for an Ender 3) and delete spaces within the file names.

Also, we should avoid starting g-code file names with underscore or any other special symbols. G-code file names starting with a number or a letter are also a solution for 3D printer not reading SD card.  

4. Subfolder G-code files

Some people want to categorize their g-code files in the SD card and create subfolders to do that. But it turns out to be another reason that the printer won't read the file.

Remove any subfolder inside the SD card and you'll find it works again.

5. Insert SD card while the printer is turned on

It's weird that when inserting a SD card while the printer is turned on, the printer won't read SD card too.  But this circumstance really happens on some 3D printers.

Hence, another procedure we should try like below:

Take out the SD card - turn off the printer - re-insert the SD card - power on the printer again.

6. Wrong format of SD card

For most users, the format of a SD card can never be a concern. But when your printer doesn't read the SD card. The format of the SD card can be also a reason for it.

Almost all 3D printers work best with SD cards in FAT32 format, and even only read FAT32 SD cards.

To figure out the problem and alter the SD card format to FAT32, let's follow below steps:

1. Insert the SD card into your PC card slot.

2. Click on "This PC" (a computer icon).

3. Right click on the SD card partition (which will be listed in the "Devices and Drives" section).

4. Click on the "Format" option from the dropdown menu.

5. Click on sub-label "File System".

6. Select "FAT32(Default)" or "W95 FAT32 (LBA)".

7. Click on "Start" button below and the SD card will be formatted to FAT32  automatically.

Formatting a SD card will erase all files inside. If you have important files inside, please do backups in advance to proceed.

7. Less free space inside the SD card

On the Ender 3, it's possible that printer won't read a SD card  with less free space.

This can be caused by software configuration files. If there is something wrong with it, less free space of the SD card makes the printer run improperly.

Delete any unnecessary files inside the SD card to get more free space.

8. Old firmware version of your printer

Old firmware version on Ender 3 can lead to SD card reading failure too. Keep firmware updated with the supplier's latest version can help you out of this issue caused SD card reading failures.

9. Faulty SD card

SD cards can be damaged if you use and keep them without care. Replace the current SD card with a new one; if it works, that is probably a problem caused by damaged SD card.

10. Damaged card slot

Card slot on a 3D printer is connected the card reader on the main board. Some users tend to push the SD card into the card slot with great force. This can damage the card slot and lead to poor connection with the card reader on the main board.

In this case, you should contact the suppliers for professional solutions.